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Abstract:

A magnetic resonance isolator includes a ferrite member, a junction
conductor that is arranged on the ferrite member and that includes a
first port, a second port, and a third port, a permanent magnet that
applies a direct current magnetic field to the ferrite member, a
capacitor as a reactance element, and a mounting substrate. A main line
arranged between the first port and the second port does not resonate,
and an end of a sub-line branching from the main line defines the third
port. The capacitor is connected to the third port and to the ground. The
phase of a wave reflected from the sub-line is adjusted so as to be
shifted by about 90 degrees at the intersection of the junction
conductor.

Claims:

1. A magnetic resonance isolator comprising: a ferrite member; a junction
conductor arranged on the ferrite member and including a first port, a
second port, and a third port; and a permanent magnet arranged to apply a
direct current magnetic field to the ferrite member; wherein the junction
conductor includes a main line arranged between the first port and the
second port and a sub-line branching from the main line and extending to
the third port, and the main line does not resonate; and a reactance
element is connected to the third port and to ground.

2. The magnetic resonance isolator according to claim 1, wherein a ground
conductor is provided on a main surface of the ferrite member.

3. The magnetic resonance isolator according to claim 1, wherein the
reactance element is a capacitor.

4. The magnetic resonance isolator according to claim 1, wherein the
reactance element is an inductor.

5. A magnetic resonance isolator comprising: a ferrite member including a
first main surface and a second main surface facing each other; a
junction conductor arranged on the first main surface of the ferrite
member and including a first port, a second port, and a third port; and a
permanent magnet arranged to apply a direct current magnetic field to the
ferrite member; wherein the junction conductor includes a main line
arranged between the first port and the second port and a sub-line
branching from the main line and extending to the third port, and the
main line does not resonate; and the sub-line includes an opposing
conductor extending along the second main surface of the ferrite member
in a direction perpendicular or substantially perpendicular to the main
line, an end of the opposing conductor defines the third port, and a
reactance element is connected to the third port and to ground.

6. The magnetic resonance isolator according to claim 5, wherein a ground
conductor is provided on the second main surface of the ferrite member.

7. The magnetic resonance isolator according to claim 5, wherein the
reactance element is a capacitor.

8. The magnetic resonance isolator according to claim 5, wherein the
reactance element is an inductor.

9. A magnetic resonance isolator comprising: a ferrite member including a
first main surface and a second main surface facing each other; a
junction conductor arranged on the first main surface of the ferrite
member and including a first port, a second port, and a third port; a
permanent magnet arranged to apply a direct current magnetic field to the
ferrite member, and a mounting substrate; wherein the junction conductor
includes a main line arranged between the first port and the second port
and a sub-line branching from the main line and extending to the third
port, and the main line does not resonate; an end of the sub-line defines
the third port and a reactance element is connected to the third port and
to ground; and the ferrite member is sandwiched between a pair of
permanent magnets respectively facing the first and second main surfaces
of the ferrite member, and mounted on the mounting substrate such that
the first and second main surfaces of the ferrite member extend in a
direction perpendicular or substantially perpendicular to a surface of
the mounting substrate.

10. The magnetic resonance isolator according to claim 9, wherein the
sub-line includes an opposing conductor extending along the second main
surface of the ferrite member in a direction perpendicular or
substantially perpendicular to the main line, and an end of the opposing
conductor defines the third port.

11. The magnetic resonance isolator according to claim 9, wherein a
ground conductor is provided on the second main surface of the ferrite
member.

12. The magnetic resonance isolator according to claim 9, wherein the
reactance element is a capacitor.

13. The magnetic resonance isolator according to claim 9, wherein the
reactance element is an inductor.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to magnetic resonance isolators, and
specifically to magnetic resonance isolators used in a microwave
frequency band, for example.

[0003] 2. Description of the Related Art

[0004] In general, an isolator has a characteristic of transmitting
signals in a predetermined direction and not transmitting signals in the
opposite direction, and is mounted in a transmitter circuit of a mobile
communication apparatus, such as a cellular phone. Known examples of
magnetic resonance isolators include isolators described in Japanese
Unexamined Patent Application Publication No. 63-260201 and Japanese
Unexamined Patent Application Publication No. 2001-326504. A magnetic
resonance isolator utilizes a phenomenon in which, when high-frequency
currents of equal amplitude whose phases differ by a quarter wavelength
flow through two lines (with four ports) perpendicular to each other, a
rotating magnetic field (circularly polarized wave) is generated at the
intersection and the circulation direction of the circularly polarized
wave is reversed in accordance with the propagation directions of the
electromagnetic waves along the two lines. In other words, by arranging a
ferrite member at the intersection and applying a static magnetic field
necessary for magnetic resonance using a permanent magnet, a positive or
negative circularly polarized wave is generated by a wave reflected from
a sub-line in accordance with the propagation direction of an
electromagnetic wave along a main line. When a positive circularly
polarized wave is generated, a signal is absorbed due to the magnetic
resonance of the ferrite member, and when a negative circularly polarized
wave is generated, no magnetic resonance is generated, whereby the signal
can pass through the intersection without attenuation. Reactance elements
for reflecting the signals are connected to the ends of the sub-line.

[0005] However, such a known magnetic resonance isolator has a large size,
for example, about 20 mm×about 20 mm for a frequency of about 2
GHz, since the main line is a quarter wavelength long so as to resonate
and two reactance elements are mounted thereon. This is problematic in
view of recent trends in mobile communication apparatuses, i.e.,
reduction in size and increasing component mounting density.

SUMMARY OF THE INVENTION

[0006] To overcome the problems described above, preferred embodiments of
the present invention provide a small low-impedance magnetic resonance
isolator.

[0007] A magnetic resonance isolator according to a first preferred
embodiment of the present invention preferably includes a ferrite member,
a junction conductor that is arranged on the ferrite member and that
includes a first port, a second port, and a third port, and a permanent
magnet that applies a direct current magnetic field to the ferrite
member. The junction conductor preferably includes a main line arranged
between the first port and the second port and a sub-line branching from
the main line and extending to the third port, and the main line does not
resonate, and a reactance element is connected to the third port and to
the ground.

[0008] In the magnetic resonance isolator according to the first preferred
embodiment, adjustment is made such that a wave reflected from the
sub-line connected to the reactance element has a phase which is
different by 90 degrees from that of an input wave from each of the first
port and the second port at the intersection of the junction conductor.
Thereby, a positive or negative circularly polarized wave is generated at
the intersection. Signal absorption or transmission is achieved through
the generation of a positive or negative circularly polarized wave as in
the related art.

[0009] In the magnetic resonance isolator according to the first preferred
embodiment, since the main line does not resonate, the length of the main
line can be decreased to a quarter wavelength or less, and since the
magnetic resonance isolator is a three-port type, only one reactance
element is required. Therefore, a very small and low-impedance magnetic
resonance isolator is obtained.

[0010] A magnetic resonance isolator according to a second preferred
embodiment of the present invention preferably includes a ferrite member
including a first main surface and a second main surface facing each
other, a junction conductor that is arranged on the first main surface of
the ferrite member and that includes a first port, a second port, and a
third port, and a permanent magnet that applies a direct current magnetic
field to the ferrite member. The junction conductor preferably includes a
main line arranged between the first port and the second port and a
sub-line branching from the main line and extending to the third port,
and the main line does not resonate. The sub-line preferably includes an
opposing conductor extending along the second main surface in a direction
perpendicular or substantially perpendicular to the main line, an end of
the opposing conductor defines the third port, and a reactance element is
connected to the third port and to the ground.

[0011] The operating principle of the magnetic resonance isolator
according to the second preferred embodiment is preferably similar to
that of the magnetic resonance isolator according to the first preferred
embodiment. In the magnetic resonance isolator according to the second
preferred embodiment, since the opposing conductor extending along the
second main surface of the ferrite member in a direction perpendicular or
substantially perpendicular to the main line is arranged so as to extend
from the sub-line, a high-frequency magnetic field is confined within the
ferrite member due to the opposing conductor such that leakage of the
magnetic flux is reduced and the insertion loss is significantly reduced
and prevented.

[0012] A magnetic resonance isolator according to a third preferred
embodiment of the present invention preferably includes a ferrite member
including a first main surface and a second main surface facing each
other, a junction conductor that is arranged on the first main surface of
the ferrite member and that includes a first port, a second port, and a
third port, a permanent magnet that applies a direct current magnetic
field to the ferrite member, and a mounting substrate. The junction
conductor preferably includes a main line arranged between the first port
and the second port and a sub-line branching from the main line and
extending to the third port, and the main line does not resonate. An end
of the sub-line defines the third port, and a reactance element is
connected to the third port and to the ground. The ferrite member is
preferably sandwiched between a pair of permanent magnets respectively
facing the first and second main surfaces, and mounted on the mounting
substrate such that the first and second main surfaces extend in a
direction perpendicular or substantially perpendicular to a surface of
the mounting substrate.

[0013] The operating principle of the magnetic resonance isolator
according to the third preferred embodiment is preferably similar to that
of the magnetic resonance isolator according to the first preferred
embodiment. In the magnetic resonance isolator according to the third
preferred embodiment, the ferrite member is preferably vertically or
substantially vertically arranged on the mounting substrate in a state in
which the ferrite member is sandwiched between a pair of permanent
magnets respectively facing the first and second main surfaces of the
ferrite member. Only a portion of the junction conductor parallel or
substantially parallel to the thickness direction and provided on the
ferrite member that is arranged vertically or substantially vertically on
the mounting substrate faces a ground electrode, the impedance is
increased and the insertion loss is reduced.

[0014] According to various preferred embodiments of the present
invention, a small low-impedance magnetic resonance isolator is obtained.

[0015] The above and other elements, features, steps, characteristics and
advantages of the present invention will become more apparent from the
following detailed description of the preferred embodiments with
reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a perspective view of a magnetic resonance isolator
according to a first preferred embodiment of the present invention.

[0017]FIG. 2 is an exploded perspective view of a magnetic resonance
isolator according to a first preferred embodiment of the present
invention.

[0018] FIGS. 3A and 3B illustrate a front view and a back view,
respectively, of a ferrite member of a magnetic resonance isolator
according to a first preferred embodiment of the present invention.

[0019]FIG. 4 is an equivalent circuit diagram of a magnetic resonance
isolator according to a first preferred embodiment of the present
invention.

[0020] FIGS. 5A to 5D are graphs illustrating the characteristics of a
magnetic resonance isolator according to a first preferred embodiment of
the present invention.

[0021]FIG. 6 is a perspective view of a magnetic resonance isolator
according to a second preferred embodiment of the present invention.

[0022] FIG. 7 is an exploded perspective view of a magnetic resonance
isolator according to a second preferred embodiment of the present
invention.

[0023] FIGS. 8A and 8B illustrate a front view and a back view,
respectively, of a ferrite member of a magnetic resonance isolator
according to a second preferred embodiment of the present invention.

[0024]FIG. 9 is an equivalent circuit diagram of a magnetic resonance
isolator according to a second preferred embodiment of the present
invention.

[0025] FIGS. 10A to 10D are graphs illustrating the characteristics of a
magnetic resonance isolator according to a second preferred embodiment of
the present invention.

[0026] FIG. 11 is a perspective view of a magnetic resonance isolator
according to a third preferred embodiment of the present invention.

[0027] FIG. 12 is an exploded perspective view of a magnetic resonance
isolator according to a third preferred embodiment of the present
invention.

[0028] FIGS. 13A and 13B illustrate a front view and a back view,
respectively of a ferrite member of a magnetic resonance isolator
according to a third preferred embodiment of the present invention.

[0029]FIG. 14 is an equivalent circuit diagram of a magnetic resonance
isolator according to a third preferred embodiment of the present
invention.

[0030] FIGS. 15A to 15D are graphs illustrating the characteristics of a
magnetic resonance isolator according to a third preferred embodiment of
the present invention.

[0031] FIG. 16 is a perspective view of a magnetic resonance isolator
according to a fourth preferred embodiment of the present invention.

[0032] FIG. 17 is an exploded perspective view of a magnetic resonance
isolator according to a fourth preferred embodiment of the present
invention.

[0033] FIGS. 18A and 18B illustrate a front view and a back view,
respectively, of a ferrite member of a magnetic resonance isolator
according to a fourth preferred embodiment of the present invention.

[0034]FIG. 19 is an equivalent circuit diagram of a magnetic resonance
isolator according to a fourth preferred embodiment of the present
invention.

[0035] FIGS. 20A to 20D are graphs illustrating the characteristics of a
magnetic resonance isolator according to a fourth preferred embodiment of
the present invention.

[0036] FIG. 21 is a perspective view of a magnetic resonance isolator
according to a fifth preferred embodiment of the present invention.

[0037]FIG. 22 is an exploded perspective view of a magnetic resonance
isolator according to a fifth preferred embodiment of the present
invention.

[0038] FIGS. 23A and 23B illustrate a front view and a back view,
respectively, of a ferrite member of a magnetic resonance isolator
according to a fifth preferred embodiment of the present invention.

[0039]FIG. 24 is an equivalent circuit diagram of a magnetic resonance
isolator according to a fifth preferred embodiment of the present
invention.

[0040] FIGS. 25A to 25D are graphs illustrating the characteristics of a
magnetic resonance isolator according to a fifth preferred embodiment of
the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, preferred embodiments of a magnetic resonance isolator
according to the present invention are described with reference to the
attached drawings. Note that in the drawings, common components or
portions are denoted by the same reference numerals and duplicated
descriptions thereof are omitted. Also note that shaded portions in the
drawings represent conductors.

First Preferred Embodiment

[0042] Referring to FIGS. 1 and 2, a magnetic resonance isolator 1A
according to a first preferred embodiment of the present invention
preferably includes a ferrite member 10, a T-shaped junction conductor 15
which is arranged on a first main surface 11 of the ferrite member 10 and
which includes three ports P1, P2, and P3, a permanent magnet 20 that
applies a direct current magnetic field to the ferrite member 10, a
capacitor C as a reactance element, and a mounting substrate 30.

[0043] The junction conductor 15 is preferably a thin film formed by
conductive metal evaporation or a thick film formed by applying
conductive paste and baking. Referring to FIGS. 3A, 3B, and 4, a main
line arranged between the first port P1 and the second port P2 facing
each other in a line, among the three ports P1, P2, and P3 of the
junction conductor 15, preferably has a length less than or equal to a
quarter wavelength so as not to resonate. A sub-line branching from the
main line on the first main surface 11 extends in a direction
perpendicular or substantially perpendicular to the main line and the end
thereof defines the third port P3. One end of the capacitor C is
connected to the third port P3. Note that the two ends (first and second
ports P1 and P2) of the main line and the end (third port P3) of the
sub-line extend over the side surfaces onto the second main surface 12 of
the ferrite member 10 (refer to FIG. 3B). Here, the main line represents
a conductor extending between the first port P1 and the second port P2,
and the sub-line represents a conductor branching from the center of the
main line and extending to the third port P3.

[0044] The mounting substrate 30 includes an input terminal electrode 31,
an output terminal electrode 32, a relay terminal electrode 33, and a
ground electrode 34 provided thereon. The ferrite member 10 and the
permanent magnet 20 preferably have the same or substantially the same
area, and the ferrite member 10 is mounted on the mounting substrate 30
in a state in which the permanent magnet 20 is pasted onto the first main
surface 11. At this time, one end (first port P1) of the main line is
connected to the input terminal electrode 31, the other end (second port
P2) is connected to the output terminal electrode 32, and the end (third
port P3) of the sub-line is connected to the relay terminal electrode 33.
One end of the capacitor C is connected to the relay terminal electrode
33 and the other end is connected to the ground electrode 34.

[0045] In the magnetic resonance isolator 1A configured as described
above, adjustment is preferably made such that a wave reflected from the
sub-line connected to the capacitor C has a phase which is different by
about 90 degrees from that of an input wave from each of the first port
P1 and the second port P2 at the intersection of the junction conductor
15. In more detail, an input wave from the first port P1 is transmitted
to the second port P2 because a negative circularly polarized wave is
generated at the intersection due to a wave reflected from the sub-line
and, thus, magnetic resonance is not generated. On the other hand, an
input wave from the second port P2 is absorbed through magnetic resonance
because a positive circularly polarized wave is generated at the
intersection due to a wave reflected from the sub-line.

[0046] With regard to the magnetic resonance isolator 1A according to the
first preferred embodiment, the input return loss is illustrated in FIG.
5A, the isolation is illustrated in FIG. 5B, the insertion loss is
illustrated in FIG. 5c, and the output return loss is illustrated in FIG.
5D. The saturation magnetization is preferably about 100 mT and the
capacitance of the capacitor C is preferably about 4 pF, for example. The
impedance between the input terminal and output terminal is preferably
about 2.4 dB, for example, and the isolation preferably is about 9.6 dB
for about 1920 MHz to about 1980 MHz, for example.

[0047] Since the main line does not resonate, the main line can be shorter
than or equal to a quarter wavelength, and in the first preferred
embodiment, the ferrite member 10 is preferably about 0.6 mm long by
about 0.6 mm wide and about 0.15 mm thick, for example. Thus, by using
the ferrite member 10, which is much smaller than existing ferrite
members, and the capacitor C as a reactance element, a small and
low-impedance magnetic resonance isolator is obtained.

[0048] The magnetic resonance isolator 1A is preferably built into, for
example, a transmitter circuit module of a mobile communication
apparatus. The mounting substrate 30 may be a printed circuit board on
which a power amplifier is mounted in the transmitter circuit module. In
this case, the ferrite member 10 including the junction conductor 15
arranged thereon and the permanent magnet 20 pasted thereon is provided
in an assembly step for the transmitter module. This is also true in the
second to fifth preferred embodiments described below.

Second Preferred Embodiment

[0049] Referring to FIG. 8B, in a magnetic resonance isolator 1B according
to a second preferred embodiment of the present invention, a ground
conductor 16 is provided on a second main surface 12 of the ferrite
member 10 and a relay terminal electrode 35 to be connected to the ground
conductor 16 is provided on the mounting substrate 30. The rest of the
configuration is preferably similar to that of the first preferred
embodiment. Thus, the second preferred embodiment produces operations and
advantages which are similar to those of the first preferred embodiment.

[0050] With regard to the magnetic resonance isolator 1B according to the
second preferred embodiment, the input return loss is illustrated in FIG.
10A, the isolation is illustrated in FIG. 10B, the insertion loss is
illustrated in FIG. 10C, and the output return loss is illustrated in
FIG. 10D. The saturation magnetization is preferably about 100 mT and the
capacitance of the capacitor C is preferably about 4 pF, for example. The
impedance between the input terminal and output terminal is preferably
about 20Ω, for example. The insertion loss is about 2.3 dB and the
isolation is about 11.1 dB for about 1920 MHz to about 1980 MHz. The
ferrite member 10 is preferably about 0.6 mm long by about 0.6 mm wide
and about 0.15 mm thick, for example.

Third Preferred Embodiment

[0051] In a magnetic resonance isolator 1C according to a third preferred
embodiment of the present invention, the end of the sub-line branching
from the main line of the junction conductor 15 on the first main surface
11 preferably includes an opposing conductor 17 (refer to FIG. 13B) which
extends along the second main surface 12 in a direction perpendicular or
substantially perpendicular to the main line. The end of the opposing
conductor 17 defines the third port P3, which is connected to the relay
terminal electrode 33. The capacitor C is connected between the relay
terminal electrode 33 and the ground electrode 34. In the third preferred
embodiment, the rest of the configuration is preferably similar to that
of the first preferred embodiment. Thus, the third preferred embodiment
produces operations and advantages which are similar to those of the
first preferred embodiment.

[0052] With regard to the magnetic resonance isolator 1C according to the
third preferred embodiment, the input return loss is illustrated in FIG.
15A, the isolation is illustrated in FIG. 15B, the insertion loss is
illustrated in FIG. 15c, and the output return loss is illustrated in
FIG. 15D. The saturation magnetization is preferably about 100 mT and the
capacitance of the capacitor C is preferably about 3 pF, for example. The
impedance between the input terminal and output terminal is preferably
about 20 Ωm, for example. The insertion loss is about 0.8 dB and
the isolation is about 9.5 dB for about 1920 MHz to about 1980 MHz. The
ferrite member 10 is preferably about 0.6 mm long by about 0.6 mm wide
and about 0.15 mm thick, for example.

[0053] In the third preferred embodiment, the insertion loss
characteristics and isolation characteristics are excellent. The reason
for this is that, since the opposing conductor 17 extending in a
direction perpendicular or substantially perpendicular to the main line
between the first and second ports P1 and P2 is arranged in a state in
which the opposing conductor 17 is connected to the third port P3, a
high-frequency magnetic field is confined within the ferrite member 10
due to the opposing conductor 17, whereby leakage of the magnetic flux is
reduced.

Fourth Preferred Embodiment

[0054] Referring to FIGS. 16 and 17, in a magnetic resonance isolator 1D
according to a fourth preferred embodiment of the present invention, an
inductor L is preferably provided as a reactance element instead of the
capacitor C. The rest of the configuration is preferably similar to that
of the third preferred embodiment. Thus, the fourth preferred embodiment
produces operations and advantages which are similar to those of the
third preferred embodiment.

[0055] With regard to the magnetic resonance isolator 1D according to the
fourth preferred embodiment, the input return loss is illustrated in FIG.
20A, the isolation is illustrated in FIG. 20B, the insertion loss is
illustrated in FIG. 20c, and the output return loss is illustrated in
FIG. 20D. The saturation magnetization is preferably about 100 mT and the
inductance of the inductor L is preferably about 2 nH, for example. The
impedance between the input terminal and output terminal is preferably
about 30Ω, for example. The insertion loss is about 1.4 dB and the
isolation is about 8.7 dB for about 1920 MHz to about 1980 MHz. The
ferrite member 10 is preferably about 0.6 mm long by about 0.6 mm wide
and about 0.15 mm thick, for example.

Fifth Preferred Embodiment

[0056] Referring to FIGS. 21, 23A, 23B, in a magnetic resonance isolator
1E according to a fifth preferred embodiment of the present invention,
the junction conductor 15 is preferably arranged on the first main
surface 11 of a ferrite member 10 so as to have a substantially
rectangular parallelepiped shape, and one end thereof defines the first
port P1 and the other end thereof defines the second port P2. The
sub-line branching from the center of the main line between the first and
second ports P1 and P2 extends from the upper surface of the ferrite
member 10 to the second main surface 12 and includes the opposing
conductor 17 extending perpendicular or substantially perpendicular to
the main line. The end of the opposing conductor 17 extends from the
second main surface 12 of the ferrite member 10 over the lower surface
onto the first main surface 11, and defines the third port P3. The main
line preferably has a length less than or equal to a quarter wavelength
so as not to resonate.

[0057] The ferrite member 10 is sandwiched between a pair of permanent
magnets 20 respectively facing the first and second main surfaces 11 and
12, and is mounted on the mounting substrate 30 in a direction such that
the first and second main surfaces 11 and 12 are perpendicular or
substantially perpendicular to the surface of the mounting substrate 30
(in other words, vertically or substantially vertically arranged).

[0058] The mounting substrate 30 preferably includes the input terminal
electrode 31, the output terminal electrode 32, the relay terminal
electrode 33, and the ground electrode 34 provided thereon. One end
(first port P1) of the junction conductor 15 is connected to the input
terminal electrode 31, the other end (second port P2) is connected to the
output terminal electrode 32, and the end (third port P3) of the opposing
conductor 17 is connected to the relay terminal electrode 33. One end of
the capacitor C is connected to the relay terminal electrode 33 and the
other end is connected to the ground electrode 34.

[0059] With regard to the magnetic resonance isolator 1E according to the
fifth preferred embodiment, the input return loss is illustrated in FIG.
25A, the isolation is illustrated in FIG. 25B, the insertion loss is
illustrated in FIG. 25c, and the output return loss is illustrated in
FIG. 25D. The saturation magnetization is preferably about 100 mT and the
capacitance of the capacitor C is preferably about 2 pF, for example. The
impedance between the input terminal and output terminal is preferably
about 20Ω, for example. The insertion loss is about 0.42 dB and the
isolation is about 7.1 dB for about 1920 MHz to about 1980 MHz. The
ferrite member 10 is preferably about 0.4 mm long by about 0.8 mm wide
and about 0.15 mm thick, for example. In the fifth preferred embodiment,
outstanding insertion loss characteristics and reductions in the size and
height are achieved.

[0060] In the fifth preferred embodiment, since only a portion of the
junction conductor 15 parallel or substantially parallel to the thickness
direction and provided on the ferrite member 10 which is arranged
vertically or substantially vertically on the mounting substrate 30 faces
a ground electrode (not illustrated), the impedance is increased and the
insertion loss is reduced.

[0061] Note that the magnetic resonance isolator according to the present
invention is not limited to the above-described preferred embodiments,
and various modifications are possible within the scope of the present
invention.

[0062] For example, the junction conductor need not be T-shaped, and the
intersection may have an angle slightly larger or smaller than about 90
degrees. In addition, the mounting substrate may have any suitable
dimensions, shape, or structure.

[0063] As described above, preferred embodiments of the present invention
are useful for magnetic resonance isolators, and specifically are
advantageous in that a reduction in size and a low impedance are
achieved.

[0064] While preferred embodiments of the present invention have been
described above, it is to be understood that variations and modifications
will be apparent to those skilled in the art without departing from the
scope and spirit of the present invention. The scope of the present
invention, therefore, is to be determined solely by the following claims.